Technologie nucléaire

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EDF builds scaled-down containment facility for research. EDF has completed building a one-third scale reactor containment facility that will be used to verify construction methods and to study ageing of the materials used in the structure.

Construction of the double-walled containment building - referred to as Vercors (from Verification Réaliste du Confinement des Réacteurs) - started in August 2013 at EDF's research and development laboratory at Renardières in Seine-et-Marne, near Paris. The structure is 30 meters in height and has a diameter of 16 meters. Some 5000 tonnes of concrete were used in its construction. It features 700 sensors and 2 kilometres of optical fibre positioned in the concrete and on both the rebar and prestressing cables for measuring temperature, deformation and water content of the concrete. EDF said that during the structure's construction, hourly measurements have been taken from the sensors from just after concreting.

Un programme d'excellence européen et un accélérateur japonais unique au monde. Reactor bolshoy moshchnosty kanalny. Appendix to Nuclear Power Reactors (Updated June 2010) The RBMK is an unusual reactor design, one of two to emerge in the Soviet Union in the 1970s.The design had several shortcomings, and was the design involved in the 1986 Chernobyl disaster.Major modifications have been made to RBMK reactors still operating.

Physics of Uranium and Nuclear Energy. (Updated September 2014) Nuclear fission is the main process generating nuclear energy.Radioactive decay of both fission products and transuranic elements formed in a reactor yield heat even after fission has ceased.Fission reactions may be moderated to increase fission or unmoderated to breed further fuel.For reactors using light water as moderator, enriched uranium is required.Isotope separation to achieve uranium enrichment is by physical processes.

Neutrons Neutrons in motion are the starting point for everything that happens in a nuclear reactor. When a neutron passes near to a heavy nucleus, for example uranium-235 (U-235), the neutron may be captured by the nucleus and this may or may not be followed by fission. Capture involves the addition of the neutron to the uranium nucleus to form a new compound nucleus.
Small Nuclear Power Reactors.
(Updated October 2015) There is revival of interest in small and simpler units for generating electricity from nuclear power, and for process heat.This interest in small and medium nuclear power reactors is driven both by a desire to reduce the impact of capital costs and to provide power away from large grid systems.The technologies involved are very diverse.

As nuclear power generation has become established since the 1950s, the size of reactor units has grown from 60 MWe to more than 1600 MWe, with corresponding economies of scale in operation. At the same time there have been many hundreds of smaller power reactors built for naval use (up to 190 MW thermal) and as neutron sourcesa, yielding enormous expertise in the engineering of small power units.

The International Atomic Energy Agency (IAEA) defines 'small' as under 300 MWe, and up to about 700 MWe as 'medium' – including many operational units from 20th century.
Generation IV Nuclear Reactors: WNA. (Updated August 2015) An international task force is developing six nuclear reactor technologies for deployment between 2020 and 2030.

Four are fast neutron reactors.All of these operate at higher temperatures than today's reactors. In particular, four are designated for hydrogen production.All six systems represent advances in sustainability, economics, safety, reliability and proliferation-resistance.Europe is pushing ahead with three of the fast reactor designs.A separate programme set up by regulators aims to develop multinational regulatory standards for Generation IV reactors.

Fast Neutron Reactors. (Updated October 2015) Fast neutron reactors are a technological step beyond conventional power reactors, but are poised to become mainstream.They offer the prospect of vastly more efficient use of uranium resources and the ability to burn actinides which are otherwise the long-lived component of high-level nuclear wastes.Some 400 reactor-years experience has been gained in operating them.Generation IV reactor designs are largely FNRs, and international collaboration on FNR designs is proceeding with high priority.

About 20 Fast Neutron Reactors (FNR) have already been operating, some since the 1950s, and some supplying electricity commercially.
Power Plant Water Use for Cooling. (Updated 30 April 2015) The amount of cooling required by any steam-cycle power plant (of a given size) is determined by its thermal efficiency.

It has essentially nothing to do with whether it is fuelled by coal, gas or uranium.However, currently operating nuclear plants often do have slightly lower thermal efficiency than coal counterparts of similar age, and coal plants discharge some waste heat with combustion gases, whereas nuclear plants rely on water.Nuclear power plants have greater flexibility in location than coal-fired plants due to fuel logistics, giving them more potential for their siting to be determined by cooling considerations. The most common types of nuclear power plants use water for cooling in two ways: To convey heat from the reactor core to the steam turbines.To remove and dump surplus heat from this steam circuit. .
* Many power plants, fossil and nuclear, have higher net output in winter than summer due to differences in cooling water temperature. 1.
Advanced Nuclear Power Reactors. Nuclear Reactor Technology.